Toggle actuated bulb clamp



'May 12, 1959 c. G; REYNARD 2,836,336

' TOGGLE ACTUATED BULB CLAMP Filed Sept. 28, 1956 I S'Sheets-Sheet 2INVENTOR. [HM/NJ) 5. RE Y/vA/w United States Patent TOGGLE ACTUATED BULBCLAM'P Chauncy G. Reynard, Marion, Ind., assignor to Radio Corporationof America, a corporation of Delaware Application September 28, 1956,Serial No. 612,782

Claims. (Cl. 279-118) This invention relates to stem sealing-in machinesfor joining together the glass stems and envelopes of radio tubes,cathode ray tubes and the like.

Normally, electronic tubes having glass envelopes are fabricated from aglass envelope and a glass stem member, which is used to close theenvelope. In many cases, the glass stem consists of a flat disk of glasshaving a central aperture therethrough. Sealed around the aperture atone side of the center of the glass stem disk is a long glass tube,which is used in the final processing of the tube as an exhausttubulation, through which the tube envelope is evacuated. To theopposite side of the glass stem disk from which the glass tubulationextends, there are normally mounted electrode structures, which functionwithin the evacuated envelope during tube operation. The electrodes aremounted on the stem prior to its being joined to the tube envelope. Thesealing of this glass stem to the tube envelope normally consists ofinserting the glass stem into a tubular portion of the envelope to apoint where the envelope closely fits around the periphery of the glassstem. Sealing fires directed onto the envelope wall at this point willsoften the glass of the envelope and cause it to flow and join with theheated periphery of the glass stern, so as to hermetically seal theenvelope wall to the glass stem completely around the periphery of thestem. After this seal or seal-in has been made, the tube envelope isevacuated through the glass tubulation and sealed off.

Normally, a sealing machine is used to insert the glass stem into theenvelope and to automatically seal the stem to the envelope wall. Suchsealing-in machines comprise a rotatable turret, which is indexedintermittently from one position to another. The turret includes supportmeans for holding the glass envelope and the stem in aligned positions.The operator loads an envelope and a stem into the holding means in aloading position. The intermittent rotation of the turret carries thebulb and stem structures from one position to the other for processinguntil the final seal has been made.

Sealing-in machines used in cathode ray production utilize a bulbsupporting means, which includes a clamp for clamping around the cathoderay bulb neck portion to hold the bulb in vertical alignment with a stempin or chuck, which supports the glass stem to be sealed into thecathode ray tube neck. Bulb clamping means, which have been used oncathode ray tube sealing-in machines, have not been always adaptable tovariable conditions, which occur during stem sealing operation. It isdesirable that such bulb clamping means be automatically adjustable tocompensate for envelope neck portions of varying diameters. Manyenvelopes which are processed by the sealing-in machines are those whichhave been salvaged from scrapped tubes or are reprocessed bulbs, inwhich the original glass stems have been broken out of the bulb and anew glass neck portion has been spliced to the envelope. In such cases,the glass neck of the cathode ray tube may be eccentric to the centerline of the bulb. Also it may have a taper, or the neck itself may besome- 2,886,336 Patented May 12, 1959 what out-of-round. It isdesirable, in such cases, that the clamping means be such that when abulb neck which is out-of-round is clamped for sealing-in, the neck willremain coaxial with the center line of the stem chuck regardless ofwhether it is clamped on a large or small diameter.

Therefore, an object of this invention is to provide a novel clampingmeans for use with a sealing-in machine for electronic tubes.

Another object of the invention is to provide a novel clamping structurefor use with a sealing-in machine for cathode ray tubes.

A further object of the invention is to provide a novel clamping meanswhich is automatically adjustable to tubes having varying diameters atthe region to be clamped.

The invention is in a clamping device for use with a sealing-in machinefor cathode ray tubes. The clamp includes a pair of aligned jaws whichare slidable for relative movement toward each other along a commonaxis. A toggle linkage connects both jaws to a tension spring forclosing the jaws upon the work article. A manually operated releaselever is utilized to open the jaws for removing the work article fromthe sealing-in machine.

Figure 1 is an elevation view of a chuck including the stem pin and bulbsupports and utilizing the novel clamping arrangement, according to theinvention;

Figure 2 is an enlarged view of a portion of the chuck shown in Figure 1and including the novel clamping device;

Figure 3 is a sectional view of Figure 2 along the section line 3--3;and

Figures 4 and 5 are, respectively, a plan and side view of amodification of the invention of Figure 1.

Figure 1 discloses a chuck or head which includes structure forsupporting tube parts in position for processing during the operation ofa sealing-in machine. The sealing-in machine consists of a turretstructure 10, only partially shown in Figure 1. The turret carries aplurality of chucks or heads 11, shown in Figure 1. Each chuck 11consists of a Vertical spindle 12 for supporting a stem assembly 14 anda bulb support 16 for supporting a glass bulb portion 18 of a cathoderay tube. The bulb support 16 is in turn supported by a pair of bulbholder posts or rods 32 which are mounted parallel to each other and tothe axis of the spindle 12. Posts 32 are fixed for simultaneous rotationabout the axis of spindle 12 so as to rotate bulb 18 and thus provide auniform heating of the seal portions of neck 20 during the sealing-inoperation. Bulb 18 also includes a tubular neck portion 20.

The stem assembly 14 for a conventional cathode ray tube consists of aglass disk 26 having a central aperture and to one side of which issealed the glass tube 22 concentric with the central aperture of disk26. On the opposite side of disk 26 from the glass tubulation 22 ismounted an electrode structure consisting of a plurality of electrodes29 fixed in a rigid assembly and mounted by lead wires or other means toa plurality of lead pins 30 sealed through the glass disk 26 in a ringarrangement concentric with the disk 26 and adjacent to its periphery.

The chuck 11 is loaded by an operator by inserting the glass exhausttubulation 22 of the stem assembly 14 into a center aperture of thespindle 12. The cathode ray tube bulb 18 is inserted neck downwardlyupon the support 16 and then clamped into a fixed position aligned withthe spindle 12 by a clamping means 24.

After loading the tube parts, the chuck or head 11 is rotated by turret10 from one position to another to perform the sealing-in operation ofthe tube. This consists of the neck 20 of bulb 18 being exposed tosealing fires from a plurality of burners 31 directed at the region ofthe neck to which disk 26 is to be sealed. Upon the neck 20 being heatedto a high temperature, spindle 12 is automatically actuated to carrystem 14 up into the neck. Further intense heating of the glass neck 2%)in the position shown in Figure 1, causes the glass of the neck to flowand seal to the glass disk 26 around its periphery. The sharp gas flamesof fires from burners 31, in this position, cut off the end of the lowerend of tube neck 2t) which drops down over the spindle l2 and isdiscarded at subsequent positons of the head Ill. The seal between neckand stem 26 is annealed, and at the final position of turret rotation,the tube 18 is unloaded by the operator. 1

' It is necessary, in the sealing-in operation, that the bulb assembly18 be rigidly and accurately held in alignment with the stem supportingspindle 12. If certain tolerances of alignment are not maintained, abulb neck portion 20 misaligned with the spindle 12, will either bebroken as the spindle 12 moves into the neck 20, or a gun electrodeassembly will be sealed into the neck at an offcenter position relativeto neck it). A positive clamping means is necessary to maintain the tubeneck 20 in its aligned position with spindle 12, as the bulb 16 iscarried from successive positions, during the sealing-in operation. Itis necesary that the clamp hold the neck 20 at spaced points along theneck so as to prevent any tilting caused by the excessively top-heavyweight of the large bulb 18 or due to any jerkiness produced by theoperation of the machine. This is particularly true when the neckportion 20 is out-of-round or is tapered for any reason of fabrication.Thus, it is preferable that the clamping means comprises at least twoclamps spaced axially along the neck 20 and which operate independentlyof each other, so that if there is any difference of neck dimensions, afirm clamping action will be maintained at each of the two spacedpoints. Furthermore, it is desirable to be able to operate such aclamping means with a single lever so that the operator can load andunload the bulbs 18 onto the head 11 with a minimum of effect and time.

In accordance with the invention, a novel clamping means 24 is fixed tothe bulb support posts 32 at the desired position by lock nuts 34. Clamp24 consists of two portions 36 and 38, which are identical, althoughoppositely disposed for clamping neck 26 in alignment with the spindle12. Each clamp portion 36 and 38 includes a pair of jaws 40 and 42slidably mounted in a block 44. Jaws 40 and 42 are fixed within a slide46 of block 44 for movement toward and away from each other along acommon axis. Movement of the jaws is provided by a pair of actuatinglevers 48 and 50, each of which are pivotally mounted at one end at 52and 54 respectively, on block 44. The other ends of levers 48 and 50comprise cylindrical heads 56 and 53 respectively and which are disposedin slots 6@ of the respective jaws 4t and 42. One link arm 62 ties eachof the actuating levers 48 and 50 to a single operating lever 64. Thelinkage arms 62 are pivotally fixed to both of the respective actuatinglevers 48 and 50. Also, the linkage arms 62 are pivotally fixedrespectively at 66 and 68 to the operating lever 64. The points 66 and68 are longitudinally spaced along the length of lever 64 and adjacentto one end 63 of lever 64. A tension spring 70 is fixed to the other end72 of lever 64 and to a fixed pin 74 of the clamp block 44.

Spring 70 urges the operating lever 64 in a clockwise direction, asshown in Figure 2, to pull the operating levers 48 and 50 and hence therespective jaws 4d and 42 toward each other to close the jaws. Thetension of spring 743 is adjusted so that the neck 20 of the tube bulbis firmly gripped when the bulb 18 is loaded into chuck l1.

Clamp portion 38 consists of the same parts, as de scribed and shown inFigure 3, for portion 36. Thus, two pairs of jaws of the clamping device24 will tightly grip the neck 20 of the cathode ray tube bulb at axiallyspaced areas so as to hold the neck 20 in alignment with the spindle 12.

The two jaws 4t) and 42 of each pair of jaws move synchronously with theother and since only a singlespring means 70 is used for each pair ofjaws, the pressure applied by the jaws of each pair is equal.Furthermore, a tube neck which may be out-of-round, when clamped by thejaws 40 and 42, will remain coaxial with the center line of the spindlel2 regardless of whether it is clamped on a large or small diameter.Also, a neck which is tapered will be firmly gripped by the two pairs ofjaws since the clamping action of each pair of jaws is completelyindependent of the clamping action of the other pair. That is, with atapered neck, the jaws of the bottom unit 38 will move in toward thecenter line farther than the jaws of the top unit 36 or vice versa. Thiskeeps the neck 20 vertical to the center line.

A single operating lever is used to open the two pairs of jaws forremoving a workpiece or in loading the machine with a new bulb. Movementof the operating levers 64, of each clamping unit, in acounter-clockwise direction against the action of springs 76respectively, is provided by a pin 76 slidably mounted in each block 44and having a rounded head abutting the lever arm 64 between the pivotpoints 66 and 72. Pins 76 are moved longitudinally by cam surfaces 78respectively formed in a metal wheel 80 rotatably mounted on a shaft 82fixed to block 44. A manually operable hand-lever 83 is utilized to turnwheel 80 about its shaft 82. A small turn of wheel 80 moves the camsurfaces 78 over the rounded ends of pins '76 in contact with wheel 80,so as to simultaneously force pins 76 inwardly against the respectiveoperating levers 64 to move the operating levers in a counter-clockwiserotation and thus to open the two pairs of jaws of both units together.

The clamping units 36 and 33 are accurately mounted in alignment withthe spindle 12. This is done by loosening lock nuts 34 on posts 32 sothat both units 36 and 38 may be moved normal to the axis of spindle 12.An arbor (not shown) is temporarily mounted vertically in the spindle 12so as to determine the center line of spindle 12 between the jaws 40 and42 of each clamping unit. The jaws are released to clamp the arbor andto automatically center themselves relative to the arbor and the centerline of spindle 12. The two units are then fixed to their mounting posts32 in these positions by tightening the lock nuts 34. The clamping unitsare released from the arbor by the actuation of the manual lever 82 andthe arbor is removed.

Some advantages of the novel clamping arrangement have been set forthabove. However, the clamping device described also lends itself to theuse of different size neck portions 20 on the same machine and allowscontinuous operation of the machine Without the necessity of delay forreadjustment or change of clamping elements to compensate for changes inneck sizes. Thus, the clamping device has universal adaptation forworkpieces having neck portions falling within a dimensional range. Theuse of a pair of clamping units as described, will enable the sealing-inmachine to be loaded by the operator without giving undue attention toaligning the bulb neck portions 20 with spindle 12. The floatingarrangement of the pairs of jaws 40 and 42 automatically centers theneck with the center line of spindle 12. Furthermore, since the pressureof the jaws 40 and 42 on portions of neck 20 is established by thetension spring 70, this clamping action has a resiliency, which is notpresent in a fixed clamp. This eliminates undue breakage of the glassparts which occurs when the clamps are rigidly fixed with no resilienceto compensate for vibration and jerking produced by the machine duringtube operation.

Figures 4 and 5 show a modification of the clamping device of Figures1-3. The same reference numerals are used in Figures 4 and 5 to indicatestructure identical to that of Figures 2 and 3. Prime numbers are usedto indicate structures in Figures 4 and 5, which are similar in designor function to structures in Figures 2 and 3.

In the device of Figures 4 and the manually operating means foropeningand closing the clamp jaws 42 consists of a crank handle 96,which is pivotally mounted at 92 to one of the clamp blocks 44. The twoclamp blocks 44', each have an operating lever 64', which is similar indesign and identical in function to the operating levers 64 of thestructure shown in Figures 2 and 3. That is, pivotal movement of eachoperating lever 64' opens and closes the respective clamp jaws 42, asdescribed above. Each operating lever 64' is moved into jaw-closingposition by a tension spring 70' connected between the free end of eachoperating lever 64 and one of two studs 94 mounted on the crank handle90. The studs 94, as shown in Figures 4 and 5, are positioned beyond thepivot point 92 from the free ends of operating levers 64'.

The movement of handle 90 is limited by a pair of stop lugs 96 and 98.The position of handle 90, in Figure 5, is one in which the springs 70have their maximum tension as the handle rests against the stop lug 96.In this position, the jaws 42 are locked against the bulb neck 20. Also,the tension of springs 70 holds handle 90 against stop lug 96 in thelocked position. To open the jaws, handle 90 is rotated clockwise fromits position shown in Figure 5 until it contacts the stop lug 98. Thisrotational movement of handle 90 relieves the tension of springs 70',and the springs themselves act to push the operating levers 64 in acounter-clockwise direction, in Figure 4, to positively open the jaws42. Thus, it can be seen that as the jaws 42 are closed, the clampingaction of the jaws is increased as the handle 90 is rotated from theposition of stop lug 98 to the position of stop lug 96. Furthermore, asshown in Figure 5, springs 70' exert on handle 90 a toggle action, sincethe handle 90 goes past a center point into the locked position againststop lug 96.

The fact, that the jaws 42 have increased clamping tension on them asthey move toward each other into clamping position, diiferentiates theoperation of the clamping device of Figures 4 and 5 from that of Figures2 and 3. Thus, the bulb neck 20 is gripped by the jaws 42 with theirmaximum clamping force by the device of Figures 4 and 5, while in thedevice of Figures 2 and 3, the clamping action is provided by a relaxingspring so that the clamping action of jaws 52 is by a spring forcesomething less than maximum. Furthermore, the toggle locking action ofsprings 70' on operating handle 90 is an advantageous feature andpermits more positive locking of the jaws by the operator.

What is claimed is:

1. A clamping device comprising a support, a pair of jaws aligned on acommon axis and slidably mounted for relative movement along said commonaxis, a pair of actuating levers pivotally mounted on said support, andeach of said actuating levers having one end connected directly to adifferent one of said jaws, an operating lever, a pair of linkage armseach pivotally connected to a respectively different one of saidactuating levers and to said operating lever, a spring connected intension between one end of said operating lever and said support tonormally urge said aligned jaws toward each other.

2. A clamping device comprising a support, a pair of jaws aligned on acommon axis and slidably mounted for relative movement along said commonaxis, a pair of actuating levers pivotally mounted on said support, andeach of said actuating levers having one end connected directly to adifferent one of said jaws, an operating lever, a pair of linkage armseach pivotally connected to a respectively different one of saidactuating levers and to said operating lever, a spring connected intension between one end of said operating lever and said support tonormally urge said aligned jaws toward each other, and manually operablemeans to move said operating lever against the tension of said spring toopen said jaws.

3. A clamping device comprising a support, a pair of jaws aligned on acommon axis and slidably mounted for relative movement along said commonaxis, a pair of actuating levers pivotally mounted on said support, eachof said actuating levers having one end directly connected to adifferent one of said jaws, an operating lever, a pair of linkage armseach pivotally connected to a respectively diiferent one of saidactuating levers and to said operating lever, a spring connected to saidoperating lever to normally urge said lever in one direction to closesaid jaws, and manually operable means on said support for moving saidoperating lever in another direction to open said jaws.

4. A clamping device comprising a support, a pair of jaws aligned on acommon axis and slidably mounted for relative movement along said commonaxis, a pair of actuating levers pivotally mounted on said support, andeach of said actuating levers having one end directly connected to adifferent one of said jaws, an operating lever, a pair of linkage armseach pivotally connected to a respectively different one of saidactuating levers and to said operating lever, a spring connected intension between one end of said operating lever and said support tonormally urge said aligned jaws toward each other, and manually operablemeans to move said operating lever against the tension of said spring toopen said jaws, said manually operable means including a rod having oneend in contact with said operating lever and a structure in contact withthe other end of said rod for forcing said rod against said operatinglever.

5. A clamping device comprising a support, a pair of jaws aligned on acommon axis and slidably mounted for relative movement along said commonaxis, an operating lever, linkage means connecting said jaws to saidoperating lever, a spring connected in tension between one end of saidoperating lever and said support to normally urge said aligned jawstoward each other, and manually operable means to move said operatinglever against the tension of said spring to open said jaws, saidmanually operable means including a rod having one end in contact withsaid operating lever and a manually operable device including a camsurface in contact with the other end of said rod for forcing said rodagainst operating lever.

6. A clamping device comprising a support, a pair of jaws aligned on acommon 'axis and slidably mounted for relative movement along saidcommon axis, an operating lever, linkage means connecting said jaws tosaid operating lever, a spring connected to said operating lever, andmeans for tensioning said spring to normally urge said aligned jawstoward each other.

7. A clamping device comprising a support, a pair of jaws aligned on acommon axis and slidably mounted for relative movement along said commonaxis, an operating lever, actuating levers, linkage means connectingsaid actuating levers to said operating lever, a handle pivotallymounted on said support, a spring connected between said operating leverand said handle for tensioning said spring to normally urge said alignedjaws toward each other.

8. A clamping device comprising a support, a pair ofjaws aligned on acommon axis and slidably mounted for relative movement along said commonaxis, an operating lever, actuating levers, linkage means connectingsaid actuating levers to said operating lever, a handle pivotallymounted on said support, a spring connected between said operating leverand a point on said handle offset from the pivot point of said handlewhereby rotation of said handle 'away from said operating lever willtension said spring to normally urge said aligned jaws toward eachother.

9. A supporting chuck for a sealing machine, said chuck comprising apair of support rods, a pair of clamps supported by said rods, each ofsaid clamps including a pair of jaws aligned on a common axis andslidably mounted for relative movement along said common axis, saidcommon axes being parallel to each other, actuating levers, an operatinglever mounted on each clamp, linkage means connecting each operatinglever to a respective pair of said actuating levers, an operating handlepivotally mounted on one of said clamps, a pair of springs, each springhaving one end connected to a diiferent one of said operating levers andthe other ends of said springs connected to said operating handle.

10. A supporting chuck for a sealing machine, said chuck comprising apair of support rods, a pair of clamps adjustably supported by saidrods, each of said clamps including a pair of jaws aligned on a commonaxis and slidably mounted for relative movement along said common axis,said common axes being parallel to each other, a pair of actuatinglevers pivotally mounted on each clamp, each of said actuating levershaving one end directly connected to each one of said jaws, an operatinglever mounted on each clamp, linkage means connecting References Citedin the file of this patent UNITED STATES PATENTS 634,276 Shaw Oct. 3,1899 1,004,260 Higbee Sept. 26, 1911 1,108,448 Julian Aug. 25, 19141,124,692 Boax Ian. 12, 1915 1,701,388 Remane Feb. 5, 1929 FOREIGNPATENTS 352,815 Germany May 5, 1922 481,940 Great Britain Mar. 16, 1938600,469 Great Britain Apr. 9, 1948

